In a relevant manufacture process of a Thin Film Transistor-Liquid Crystal Display (TFT-LCD), electrode patterns need to be formed on a surface of a substrate by wet-etching. When performing the wet-etching, etching agents need to be sprayed onto the substrate to form the patterns on the substrate, and such spraying occurs during conveying the substrate. However, spraying the etching agents on the substrate may generate a relatively large force on the substrate, such that large friction occurs between the substrate and rollers of a substrate conveying device and hinders the substrate from being conveyed. For this, a roller train is used to convey the substrate when spraying the etching agents onto the substrate. That is, the substrate is placed between two rollers arranged oppositely to each other and is conveyed by the two rollers, and thereby the substrate is conveyed.
However, during conveying the substrate, an upper roller and a lower roller of the roller train may displacement axially relative to each other, resulting in misalignment between the upper roller and the lower roller. Such misalignment may cause deformation or even crush of the substrate between the two rollers.